Nozomi Katagiri

Control effects of steer-by-wire system for motorcycles on lane-keeping performance

This study discusses the control effects of the steer-by-wire (SBW) system for motorcycles on the lane-keeping performance by examining computer simulation with a rider-vehicle system which consists of a simplified vehicle model, a rider control model and the controller of the SBW system. The SBW system, which compensates the rolling angle deviation between the desired rolling angle intended by the rider and the actual rolling angle, improves the lane-keeping performance of the rider-vehicle system under the steering torque disturbance. The SBW system is, on the other hand, not effective in the lane-keeping performance under the lateral force disturbance. In addition, the lane-keeping assistance (LKA) system is applied to the SBW system and the cooperativeness of the SBW and the LKA systems is examined. The LKA system improves the lane-keeping performance of the SBW system under not only the steering torque disturbance but also the lateral force disturbance.

Design of lane tracking controller for motorcycles

This study examines a lane tracking control system for motorcycles to develop a lane keeping assistance system. We apply the optimal control theory based on a model-based control to the controller to follow a desired lane. By examining computer simulation using a simplified vehicle model, a good lane tracking performance is realized by evaluating the lateral displacement of gravity in the cost function of the optimal control. The tracking performance is improved by increasing the weight for the lateral displacement of the center of gravity. Furthermore, evaluating the lateral displacement at the virtual point ahead of the vehicle, which is defined by synthesizing the lateral displacement of the vehicle gravity and the yawing angle, copes with both lane tracking performance and convergence with suppressing undesirable yawing motion.